Mining company Terramin said it would maintain its zinc mine, south of Adelaide, once production ended after September.

The mine closure means 115 people will lose their jobs.

Terramin spent $71 million to open the mine near Strathalbyn in 2008 but, five years on, company CEO Martin Janes said it had run out of good-quality zinc which was easy to mine.

"We certainly have lost a little bit of time off the mine and I'd say that economically the mine has not been a huge success story," he said.

Mr Janes said a handful of employees would maintain the site beyond September and keep exploring for further deposits.

But he said the price of zinc would need to rise substantially for production to resume.

Aaron Cartledge of the mining union said it was keen to meet company officials this week to discuss workers' entitlements.

"We want to have a look at the nature of the redundancies packages that are on offer, also talk to them about retraining or redeployment or if they have other connections in the mining industry," he said.